1. Field of the Invention
This invention relates generally to grain drills having a forwardly disposed seed spout and a rearwardly disposed fertilizer spout, and pertains more particularly to a means for determining where the fertilizer is deposited in a furrow with respect to the seed.
2. Description of the Prior Art
While a number of grain drills have been marketed without any means for introducing fertilizer into the furrow, a number of fertilizer-grain drills have been employed. Some of these grain drills deposit a mixture of seed and fertilizer through a single tube or spout. Others make use of two tubes or spouts, the seed flowing downwardly through one spout and the fertilizer through the other.
If too much fertilizer is deposited directly onto the seed, then so-called burning can result which interferes with the germination of the seed and also can injure young plants after the seeds have germinated. While various metering devices can control the mixture of seed and fertilizer, this results only in an optimum relation initially and does not provide a latent supply of nutrients that will become available from the fertilizer later on.